Motion transmitting mechanism for air transmitters



July 8, 1958 B. JONES 2,842,143

MOTION TRANSMITTING MECHANISM FOR AIR TRANSMITTERS Filed Aug. 25, 1955 2 Sheets-Sheet 1 v ea anew/v ms/5 45 I INVENTOR.

2 2 0. Z. 51 ag 742% HITQQNEVS' July 8, 1958 I B. JONES 2,842,148

MOTION TRANSMITTING MECHANISM FOR AIR TRANSMITTERS Filed Aug. 25, 1955 2 Sheets-Sheet 2 Alli V W5 s4 7\ /i Q 7 75 m rig, 67

lillla- IiH 50270 JONES,

INVENTOR.

Maw

United States Paten 2,842,148 MOTION TRANSMITTING EcHjANisM FOR AIR TRANSMITTERS Barton Jones, Los Angeles, Calif. Application August 25, 1955, Serial No. 530,477

4 Claims. (Cl. 137--'85) This invention relates to an im rovement in' mot-ion transmitting mechanisms for air't'ransmitters' and the like, and may be regarded as an improvement over the construction disclosed in my application for United States Letters Patent Serial No. 411,990 filed February 23, 1954 (since abandoned.)

Explanatory of the present invention, there have heretofore been designed air transmitters wherein a relay valve that is supplied with air under pressure is actuated by the back pressure developed by a flapper engageable with a nozzle through which air from-the source of supply escapes after passing through a restricter. When the flapper is lifted from the nozzle to permit air to be discharged through the nozzle more freely there is a minimum of back pressure. This reduction in back pressure is effective to cause the relay valve to close and to cause the pressure of the transmitted air' to be reduced by releasing it to atmosphere. Conversely, when" the flapper closes against the nozzle back pressure developed in the nozzle quickly builds up causing the relay valve to open and thus release a greater amount of compressed air from the source of supply so that it may be transmitted to the receiver. The flapper is actuated by means of a driver or an excitcr which is moved by a suitable mechanism and the function of the air transmitter is to transmit air pressure to a receiver at a pressure which will bear a direct relationship to the movements of the driver or exciter.

It has been proposed to fulcrum the flapper on a repositioning bellows which is subject to and is influenced by the pressure of the transmitted air. The purpose of this is so that in all positions of the exciter or driver the flapper is in a position to be immediately depressed or released thereby for movement towards or away from the nozzle. In this manner, if the exciter or driver is in a position requiring the transmission of air at one pressure and shifts slightly to require the air that is transmitted to be at a lower pressure the. flapper will be maintained at all times in a position so as to be instantly influenced thereby. Likewise, if the exciter or driver shifts slightly to require that the air that is transmitted to be at a higher pressure the flapper will be maintained at all times in a position with relation to the nozzle so as to be instantlyinfluenced thereby. 7

Very frequently the mechanism which actuates the exciter or driver is in the form of a diflerential pressure responsive device of the type disclosed in my United States Letters Patent No. 2,400,048, issued May 7 1946, wherein there are two opposed metallic'bellows which are subjected to the pressures between which a differential may exist. A torque tube or equivalent device transmits the motion of these bellows to the exterior of the device and this torque tube may constitute the driver or exciter of the present invention.

The metallic bellows of the differential pressure responsive device and also the metallic bellows ofthe air transmitter are not always linear in theirmovementsin response to the pressures to which they may be subjected'. In some instances the eifect of the bellows is such that they may have a combined effect that may be regarded as a plus error wherein the movements of the bellows are greater than the movements which they should have in response to the pressures to which they are subjected. In other instances, the bellows may have a combined effect of what may be regarded as a minus error wherein the movements of the bellows are actually less than the movements that they should have in response to the pressures to which they are subjected.

In still further instances, the bellows may have neutralizing'eflects one upon the other or may inherently have movements which exactly correspond to the pressures to which they are subjected, in which case the combined eife'ct is neither a plus error nor a minus error.

A primary object of the present invention is to provide a very simple and readily adjustable mechanism of the linkage train between the torque tube or exciter and the flapper which will enable these errors, if they exist, to be easily corrected and compensated for. Consequently, regardless of what type of error the bellows may have with respect to their pressures, if in fact such error exists, the movement of the flapper may be made to conform to the pressures which are intended to actuate it. Thus, a plus error, if it exists, may be corrected or neutralized, and likewise a minus error, if it exists, may be corrected or neutralized. If the bellows either inherently have no error or the combined errors of the various bellows neutralize each other the linkage train may be so adjusted that no correction or compensation is made. i

More specifically, an object of the invention is to provide a means for fulcruming the flapper of an air transmitter on the repositioning bellows of the air transmitter so that the fulcruming-providing means has a slidable engagement with it between the flapper and the repositioning bellows as distinguished from a pivotal connection between the flapper and the repositioning bellows. In this manner, reactionary forces on the repositioning bellows remain constant and do not vary with different positions assumed by the repositioning bellows. Consequently, in different positions assumed by the apparatus there is no tendency to distort or abnormally load the repositioning bellows in the course of movement of the repositioning bellows from one position to another.

Still a further object of the invention is to provide a novel and simple arrangement of parts and to provide a simple and virtually frictionless hinge between the flapper and the exciter or driver so that the end of the flapper which is on the opposite side of the fulcrum-providing means from the nozzle will be actuated properly by the ex'citer but without disturbing or modifying influences.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a sectional View of an air transmitter illustrating the motiontransmitting mechanism embodying the present invention as having been applied thereto;-

Fig. 2 is a partial view in horizontal section taken substantially upon the line 2-2 upon Fig. l in the direction indicated,- and Fig. 3 is a partial view in vertical section taken substantially'upon the line 3-3 upon Fig. l in the direction indicated.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the transmitter illustrated on Fig. '1 is generally similar in' construction. to that disclosed in my copenda ing application Serial No. 326,119, filed December 15, 1952 now Patent No. 2,7l8,896, and consists essentially of a base to which compressed air is supplied from a source of supply through an inlet port 11. The compressed air after passing through a filter l2 retained in place by a removable nut 13 passes into a valve chamber 14. A portion of the air supplied to the valve chamber 14 is conducted through a passage 15, see 'Fig. 3, to a restricter 16. After passing through the restricter this portion of the air is conducted by means of passages 17 and 18 to the interior of a lower bellows 19 which is mounted on the under side of a horizontal partition plate 20.

Within the bellows 19 there is an inner bellows 21 which is also mounted on the under side of the partition plate and the lower ends of both bellows are connected together and to a rigid connecting stem 22. The air that is conducted from the restricter through passages 17 and 18 is discharged into the space between the two bellows, and from this space it finds egress through passages 23 and 24 to a nozzle 25 through which the air is more or less continuously discharged. The nozzle 25 is threadedly mounted for vertical adjustment on a nozzle holder 26.

On the upper side of the partition plate 20 there are two bellows, the outer bellows being indicated at 27 and the inner bellows being indicated at 28. The upper ends of both bellows are connected together and to the upper end of the connecting stem 22. The effective areas of the outer bellows 19 and 27 are equal to each other, and in a similar manner, the effective areas of the inner bellows 21 and 23 are equal to each other. The stem 22 being a rigid stem, causes the outer or movable ends of all of the bellows to move vertically in unison. The space between the upper bellows 27 and 28 is connected through passages 2) and 30 to an upper housing, generally indicated at 31 and to atmosphere through an outlet port 32.

Within the stem 22 there is a valve seat 33 on which a valve closure 34 is adapted to seat. This valve closure has a stem 35 on which a valve closure 36 is adjustably mounted, such as by being threaded thereon and locked in adjusted position by means of a locknut 37. The lower valve closure is adapted to seat on a seat 38 arranged at the top of the chamber 14. In the stem 22 there is a transversely extending bore or passage 39 which is located above the valve seat 34 and which discharges into the interior of the inner bellows 21 when the closure 34 is open or unseated. From the inner bellows air that is allowed to escape from the chamber 40 when the closure 34 is opened or unseated may find egress through the passages 29 and 30 to atmosphere at 32. 41 indicates the outlet which is connected to the chamber 40 through a filter 42 and a passage 43. A filter is preferably employed at this point due to the fact that under certain conditions there may be a tendency toward back flow from the receiver to the chamber 40.

It will be appreciated from the above-described construction that if flow of air through the nozzle 25 is retarded or restricted, that the back pressure developed by such a restriction is effective on the bellows 19 and 21 to urge these bellows to expand. When these bellows expand downwardly they cause the seat 33 to engage the closure 34, thus closing the chamber 40 against the escape of air. The closure 36 may be unseated under these circumstances, allowing compressed air from the inlet 11 to enter the chamber 40 and to pass therefrom to the outlet 41 and to the receiver. The upper bellows 27 is externally subjected to whatever pressure exists in the chamber 40, passages 44 in the partition providing free communication between the top and bottom of the chamber through the partition plate. If air is allowed to escape more freely through the nozzle 25 the back pressure that is effective on the bellows 19 and 21 is reduced, and these bellows are consequently permitted to contract.

4 When these bellows contract the stem 22 is lifted so that the closure 36 may be seated by virtue of a compression spring 45. The valve seat 33 may be lifted above the closure 34 and air in the chamber 40 may consequently be allowed to escape to atmosphere through passages 39, 29, 30, and 32. This escape of air from the chamber 40 reduces the pressure of the air that is transmitted to the receiver through the outlet 41. It will thus be understood that if egress of air through the nozzle 25 is retarded that the pressure transmitted through the outlet 41 to the receiver will be increased, and conversely if the restriction on the nozzle 25 is reduced that the pressure of air transmitted through outlet 41 to the receiver will be decreased.

On top of the chamber 40 there is mounted a repositioning bellows 50, the interior of which is in communication with the chamber 40 through passages 51 so that this repositioning bellows is subject to and is influenced by thetransmitted pressurethat is transmitted to the receiver through the outlet 41 and which exists in the chamber 40. This bellows is urged into its contracted position by means of tension springs 52.

On the cap of the bellows there is a threaded stem 53 that is threaded into a bushing 54 and into which there is also threaded a stem 55 carrying shoulder 56 and 57 engageable with the top of the chamber 40 to locate vertical movement of the repositioning bellows. The stem 53 is locked in vertically adjusted position such as by locknuts 57.

On the top of this stern there is a horizontally disposed rod 58 on which a fulcrum pin 59 is slidably disposed. The flapper 60 which is over the nozzle 25 and which increases and decreases the rate of flow through the nozzle rests on top of the fulcrum pin 59 and is slidable relatively thereto. In other words, the fulcrum pin 59 is slidable between the under side of the flapper 60 and the horizontal rod 58 which is raised and lowered by the repositioning bellows 50. On the opposite end of the flapper from the nozzle 25 there is secured thereto a U-shaped spring 61 which in turn is connected to an arm 62 which is on a crank 63 on an exciter or driver shaft 64. This driver shaft or exciter shaft may be oscillated by any suitable mechanism such as for example a differential pressure responsive means of the type dis closed in my prior U. S. Letters Patent No. 2,400,048. The U-shaped spring 61 forms a type of frictional hinge connecting the arm 62 with the flapper 60 and when the exciting or driving shaft 64 turns in one direction it is effective to depress the end of the flapper 60, causing it to fulcrum about the fulcrum pin 59 and to be elevated with respect to the nozzle 25. Conversely, if the exciting or driving shaft 64 rotates in the opposite direction, spring 61 is elevated and the flapper 60 fulcruming on the ful: crum pin 59 may approach the nozzle 25 more closely.

As above explained, the action of the various bellows frequently is not linear and the combined actions of all of the bellows may result in either a plus error or a minus error, or no error at all. To compensate for these errors the fulcrum pin 59 is located on the end of an arm 65 which, in turn, has a parallel pin 66 which is parallel to the fulcrum pin 59. This pin is rotatably mounted on a bracket 67 that is rotatably adjustable by means of a screw 68 on a plate 69. The plate 69 is transversely adjustable with relation to a supporting boss 70 on loosening a screw 71 that extends through a slot 72 in the plate. Fine adjustment of this plate in a transverse directiori is accomplished by means of an adjusting screw 73.

It will be appreciated by the above-described construction that lateral adjustment of the plate 69 produces lateral adjustment of the fulcrum pin 59 and that this varies the two lever arms, namely the distance between the ful crum pin 59 and the arm 62 and the distance between the fulcrum pin 59 and the nozzle 25. ,Consequently, calibration, particularly the range of calibration, can be easily accomplished by merely adjusting the position of the plate 69.

With the arrangement above described, it will be appreciated that the fulcrum pin 59, in the course of its upward and downward movements, is caused to swing about the axis of the pin 66 which is remote from the fulcrum pin. Thus, in the position shown in Fig. 1, if the respositioning bellows 50 is expanded and the fulcrum 59 is caused to be lifted by the rod 58, the fulcrum pin swings through an arc whose center is the axis of the pin 66 and which is remotely located below and to the right of the fulcrum pin. This position of the bracket 67 causes one type of error to be compensated for in that as the fulcrum pin 59 is caused to swing about pin 66 as a center, it will slide toward the right between the flapper 60 and the rod 58 and thus shorten the lever arm between the fulcrum pin and arm 62. If screw 68 is loosened and bracket 67 is rotated in a counterclockwise direction from the position shown to position the axis of pin 66 above and to the right of fulcrum pin 59, the fulcrum pin will be caused to move through another are whose center is then above and to the right of the fulcrum pin. In such a position if the repositioning bellows 50 is expanded the fulcrum pin 59 will be lifted by the rod 58 and will be caused to slide toward the left between the rod 58 and the flapper 60. This has the effect of lengthening the distance between the fulcrum pin 59 and the arm 62 and compensates for the other type of error. If the axis of pin 66 is positioned horizontally even with fulcrum pin 59 then fulcrum pin 59 will be caused to pass through an are that is substantially vertical and in this latter position, no eror in the bellows is compensated for. Adjustment of the bracket 67 with relation to screw 68 when the screw is loosened occurs about an axis that is coincident with the axis of the fulcrum pin 59 and with the exciting or driver shaft 64.

By virtue of the fact that the fulcrum pin 59 is slidable between the rod 58 and the under side of the flapper 60, as distinguished from being pivotally connected to either of these parts, it will be appreciated that the various positions assumed by the fulcrum pin have no distorting effect or reactionary effect on the repositioning bellows 50. Regardless of the position given the bracket 67 and regardless of the position of the are that the fulcrum pin 59 may be caused to follow in the course of its movements the repositioning bellows 50 remains uninfluenced thereby. Under all circumstances, the fulcrum pin 59 merely slides back and forth between the rod 58 and the flapper 60.

It will be appreciated from the above-described construction that the linkage train between the exciter or driver 64 and that end of the flapper 60 which overlies the nozzle is very simple in construction and can be easily and quickly adjusted so as to compensate for various errors in the entire apparatus that may be injected into the mechanism by inherent characteristics in the bellows themselves.

, Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

vl. In an air transmitter, an exciting crank arm, a nozzle and a flapper therefor, a repositioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the repositioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being slidable between the flapper and the repositioning bellows and being swingable about an axis remote from the point where it fulcrums the flapper and being confined to a swinging movement about said axis.

2. In an air transmitter, an exciting crank arm, a nozzle and a flapper therefor, a repositioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the repositioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being slidable between the flapper and the repositioning bellows and being swingable about an axis remote from the point where it fulcrums the flapper and being confined to a swinging movement about said axis, and means for adjusting the position of the axis about which the fulcruming means is swingable.

3. In an air transmitter, an exciting crank arm, a nozzle and a flapper therefor, a repositioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the repositioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being slidable between the flapper and the repositioning bellows and being swingable about an axis remote from the point where it fulcrums the flapper, and means for adjusting the position of the axis about which the fulcruming means is swingable through an arc, the center of which is coincident with the point where the fulcruming means fulcrums the flapper.

4. In an air transmitter, an exciting crank arm, a nozzle and a flapper therefor, a repositioning bellows subjected to the transmitted pressure, means fulcruming the flapper on the repositioning bellows, means connecting the flapper to the exciting crank arm, said fulcruming means being slidable between the flapper and the repositioning bellows and being swingable about an axis remote from the point where it fulcrums' the flapper, and means for adjusting the position of the axis about which the fulcruming means is swingable through an arc, the center of which is coincident with the axis of rotation of the exciting crank arm.

References Cited in the file of this patent UNITED STATES PATENTS Jones Sept. 27, 1955 

